\ifpackageavailable{pflscape}
{\usepackage{pdflscape}}
{\usepackage{lscape}}

\ifpackageavailable{lipsum}
{
  \usepackage{lipsum}
}
{
  \newcommand{\lipsum}[1][]{
    \begin{center}
      Sorry, \textsl{lipsum} package is not available.
    \end{center}
  }
}

\ifpackageavailable{todonotes}
{
  \usepackage{todonotes}
  \usepackage{xcolor}
}
{
  \newcommand{\todo}[2][]
  {
    \begin{center}
      \textbf{TODO : } ##2
    \end{center}
  }
  \infomessage{Todo support disabled.}
}

\usepackage{multicol}

\ifpackageavailable{varioref}
{\usepackage{varioref}}
{}

\ifpackageavailable{float}
{\usepackage{float}}
{}
